Genipin suppression of fibrogenic behaviors of the α-TN4 lens epithelial cell line

Geniposide reduced oxidative stress-induced apoptosis in HK-2 cell through PI3K/AKT3/FOXO1 by m6A modification

Exogenous hydrogen peroxide (H2O2) may generate excessive oxidative stress, inducing renal cell apoptosis related with kidney dysfunction. Geniposide (GP) belongs to the iridoid compound with anti-inflammatory, antioxidant and anti-apoptotic effects. This study aimed to observe the intervention effect of GP on H2O2-induced apoptosis in human kidney-2 (HK-2) cells and to explore its potential mechanism in relation to N6-methyladenosine (m6A) RNA methylation. Cell viability, apotosis rate and cell cycle were tested separately after different treatments. The mRNA and protein levels of m6A related enzymes and phosphoinositide 3-kinase (PI3K)/a serine/threonine-specific protein kinase 3 (AKT3)/forkhead boxo 1 (FOXO1) and superoxide dismutase 2 (SOD2) were detected by reverse transcription-quantitative real-time PCR (RT-qPCR) and Western blot. The whole m6A methyltransferase activity and the m6A content were measured by ELISA-like colorimetric methods. The changes of m6A methylation levels of PI3K/AKT3/FOXO1 and SOD2 were determined by methylated RNA immunoprecipitation (MeRIP)-qPCR. Multiple comparisons were performed by ANOVA with Turkey's post hoc test. Exposed to 400 μmol/L H2O2, cells were arrested in G1 phase and the apoptosis rate increased, which were significantly alleviated by GP. Compared with the H2O2 apoptosis group, both the whole m6A RNA methyltransferase activity and the m6A contents were increased due to GP intervention. Besides, the SOD2 protein was increased, while PI3K and FOXO1 decreased. The m6A methylation level of AKT3 was negatively correlated with its protein level. Taken together, GP affects the global m6A methylation microenvironment and regulates the expression of PI3K/AKT3/FOXO1 signaling pathway via m6A modification, alleviating cell cycle arrest and apoptosis caused by oxidative stress in HK-2 cells with a good application prospect.

NIR-triggered drug delivery system for chemo-photothermal therapy of posterior capsule opacification

Posterior capsule opacification (PCO) is the most common complication after cataract surgery and is likely to cause the second loss of vision. Pharmacological PCO prophylaxis has been proved to be effective, yet no clinical option is available due to the lack of a suitable mode of administration. In this work, we propose a unique concept of NIR dual-triggered drug release from black phosphorus (BP)-based implantable intraocular lens (IOL) for controlled drug release and chemo-photothermal combination therapy of PCO. Here, IOL is used as a "reservoir" of doxorubicin-loaded black phosphorus (BP-DOX), and BP is used as NIR activation agent for controlled drug release and photothermal therapy. This BP-DOX integrated IOL, namely BP-DOX@IOL, shows the characteristics of good transmittance, good mechanical property, NIR dual-triggered drug release behaviors, and excellent photothermal efficacy. In vivo studies reveal that there is no PCO occurrence in rabbits' model by using BP-DOX@IOL combined NIR irradiation, which exhibits distinct superiority on inhibiting PCO than the control group (100% PCO occurrence) 28 days post-surgery. This novel IOL drug delivery system would be a promising strategy for the future clinical application for PCO prophylaxis and treatment.

Understanding Drivers of Ocular Fibrosis: Current and Future Therapeutic Perspectives

Ocular fibrosis leads to severe visual impairment and blindness worldwide, being a major area of unmet need in ophthalmology and medicine. To date, the only available treatments are antimetabolite drugs that have significant potentially blinding side effects, such as tissue damage and infection. There is thus an urgent need to identify novel targets to prevent/treat scarring and postsurgical fibrosis in the eye. In this review, the latest progress in biological mechanisms underlying ocular fibrosis are discussed. We also summarize the current knowledge on preclinical studies based on viral and non-viral gene therapy, as well as chemical inhibitors, for targeting TGFβ or downstream effectors in fibrotic disorders of the eye. Moreover, the role of angiogenetic and biomechanical factors in ocular fibrosis is discussed, focusing on related preclinical treatment approaches. Moreover, we describe available evidence on clinical studies investigating the use of therapies targeting TGFβ-dependent pathways, angiogenetic factors, and biomechanical factors, alone or in combination with other strategies, in ocular tissue fibrosis. Finally, the recent progress in cell-based therapies for treating fibrotic eye disorders is discussed. The increasing knowledge of these disorders in the eye and the promising results from testing of novel targeted therapies could offer viable perspectives for translation into clinical use.

Optimizing Genipin Concentration for Corneal Collagen Cross-Linking: An ex vivo Study

PURPOSE

Studying genipin variable concentrations, treatment durations, and delivery methods as a substance to increase corneal stiffness by inducing corneal collagen cross-linking (CXL).

MATERIALS AND METHODS

100 bovine corneas treated with different genipin concentrations (0.1, 0.5, and 1%) and treatment durations (15 min, 40 min, 2 h, and 3 days) through different delivery methods compared to 10 controls treated with riboflavin/UV. Histology examination, enzymatic digestion with collagenase and thermal differential scanning calorimetry were performed on the different samples.

RESULTS

Bovine corneas soaked in 0.5% genipin morphologically showed 4.7% CXL in comparison to 5.6% in controls (p < 0.05). Corneas treated with topical 0.5% genipin, by a 140-µL drop applied hourly for 2 h, showed 7% corneal CXL. Corneas treated with topical genipin 0.5% for 30 min, 1 and 2 h showed 54 ± 6, 40 ± 7, and 39 ± 9% enzymatic degradation, respectively, in comparison to controls (74%). Corneas treated with 0.5% genipin for 1, 2, and 8 h showed higher thermal denaturation resistance (Td values of 64.9 ± 0.3, 64.7 ± 0.0 and 67.3 ± 0.9), respectively, in comparison to the control group (64.6 ± 0.5) (p < 0.05).

CONCLUSIONS

Genipin 0.5%, in a 140-µL drop applied hourly for 2 h, showed better potential to enhance corneal stiffness and stability through inducing CXL.

Current scenario for the hepatoprotective effects of Inchinkoto, a traditional herbal medicine, and its clinical application in liver surgery: A review

Inchinkoto (ICKT) is one of the most commonly used herbal medicines as a hepatoprotective agent. Among the numerous chemical compounds included in ICKT, geniposide is the most abundant component. Geniposide, after p.o. intake, is converted to the active metabolite genipin by intestinal bacteria and is absorbed in the portal circulation. The biological properties of ICKT and genipin have been studied in numerous experiments. Administration of ICKT or genipin exerts choleretic effects through upregulation of multidrug resistance-associated protein 2 in hepatocytes. ICKT also exerts an anti-apoptotic action through inhibition of transforming growth factor-β1- or tumor necrosis factor-α-dependent signaling pathways. The excessive inflammatory response induced by various hepatic stresses is also attenuated by ICKT pre-administration. Moreover, ICKT upregulates antioxidant enzymes in the liver under conditions of oxidative stress. These experimental results suggest potential benefit of ICKT in liver disease and particularly in hepatic surgery, which justify further well-designed controlled clinical study. To date, however, clinical data regarding the benefit of ICKT for liver surgery are rare. This review article summarized and discussed recent evidence relating to the hepatoprotective effects of ICKT in the field of basic and clinical science.

A systematic review of the wound-healing effects of monoterpenes and iridoid derivatives

The search for more effective and lower cost therapeutic approaches for wound healing remains a challenge for modern medicine. In the search for new therapeutic options, plants and their metabolites are a great source of novel biomolecules. Among their constituents, the monoterpenes represent 90% of essential oils, and have a variety of structures with several activities such as antimicrobial, anti-inflammatory, antioxidant and wound healing. Based on that, and also due to the lack of reviews concerning the wound-healing activity of monoterpenes, we performed this systematic review-which provides an overview of their characteristics and mechanisms of action. In this search, the terms "terpenes", "monoterpenes", "wound healing" and "wound closure techniques" were used to retrieve articles published in LILACS, PUBMED and EMBASE until May 2013. Seven papers were found concerning the potential wound healing effect of five compouds (three monoterpenes and two iridoid derivatives) in preclinical studies. Among the products used for wound care, the films were the most studied pharmaceutical form. Monoterpenes are a class of compounds of great diversity of biological activities and therapeutic potential. The data reviewed here suggest that monoterpenes, although poorly studied in this context, are promising compounds for the treatment of chronic wound conditions.

Collagen crosslinking of porcine sclera using genipin

PURPOSE

To evaluate the effect of collagen cross-linking induced by genipin in porcine sclera.

METHODS

Porcine cadaver eyes were treated with genipin at concentrations (by w/v) of 0.01%, 0.03%, 0.1%, 0.3%, 1.0% for 15 and 30 min. Riboflavin/ultraviolet A(UVA)-treated and untreated samples were used as controls. After treatment, scleral strips of 4.0 × 10.0 mm were cut. Twenty-four hours later, the stress-strain parameters of the strips were measured using a biomaterial microtester. The stress and Young's modulus at 8% strain were evaluated.

RESULTS

Compared with untreated groups, after treatment with genipin for 15 min, the stress was increased by 66-246%, depending on the concentration of genipin. As for the 30-min groups, the stress was 171-444% higher than that of the control. The difference of the Young's modulus between genipin 15-min groups, except the 0.01% groups (p = 0.095), also had statistical significance (p < 0.05). The Young's modulus had significant difference between the untreated group and the genipin 30-min groups (all p < 0.05). Of 0.3% genipin for 15 min or 0.01% genipin for 30 min had a similar stress-strain curve with those of eyes treated with the riboflavin/UVA group. The sclera exhibited a bluish colour which became deeper with increase concentration and cross-linking time.

CONCLUSIONS

Collagen cross-linking induced by genipin could increase the biomechanical strength in porcine sclera. The effect depends on the concentration and treatment time of genipin.

Polymethoxyflavones as agents that prevent formation of cataract: nobiletin congeners show potent growth inhibitory effects in human lens epithelial cells

Posterior capsular opacification (PCO) is the most frequent complication and the primary reason for visual decrease after extracapsular cataract surgery. The proliferation and migration of leftover lens epithelial cells (LECs) after surgery may contribute to the development of PCO. To prevent PCO, a rational approach would be to inhibit both the proliferation and the migration of LECs using nontoxic xenobiotics. Nobiletin, one of the most abundant polymethoxyflavones (PMFs) in citrus peel, and its synthetic congeners displayed a potent inhibition of LEC proliferation. Structural features which enhance anti-proliferative activity have also been discussed.

Up-regulation of TIMP-1 by genipin inhibits MMP-2 activities and suppresses the metastatic potential of human hepatocellular carcinoma

Aim of the Study

Hepatocellular carcinoma is one of the most malignant human cancers with high metastatic potential. The aim of this study is to investigate the anti-metastatic effect of genipin and its underlying mechanism.

Experimental Approach

The anti-metastatic potential of genipin was evaluated by both cell and animal model. Wound healing and invasion chamber assays were introduced to examine the anti-migration and anti-invasion action of genipin in human hepatocellular carcinoma cell HepG2 and MHCC97L; orthotopical implantation model was used for in vivo evaluation. Gelatin Zymography, Immunoblotting, quantitative real-time polymerase chain reaction and ELISA assays were used to study the mechanisms underlying genipin’s anti-metastatic effect.

Key Results

Genipin suppresses the motility and invasiveness of HepG2 and MHCC97L at non-toxic doses, which may be correlated to the inhibition of genipin on MMP-2 activities in the cells. No significant reduced expression of MMP-2 was observed either at mRNA or at protein level. Furthermore, genipin could specifically up-regulate the expression of TIMP-1, the endogenous inhibitor of MMP-2 activities. Silencing of TIMP-1 by RNA interference abolishes genipin’s anti-metastaic effect. Activation of p38 MAPK signaling was observed in genipin-treated cells, which is responsible for the TIMP-1 overexpression and MMP-2 inhibition. Presence of SB202190, the p38 MAPK inhibitor, attenuates the anti-metastatic potential of genipin in hepatocellular carcinoma. Orthotopical implantation model showed that genipin could suppress the intrahepatic metastatic as well as tumor expansion in liver without exhibiting potent toxicity.

Conclusion

Our findings demonstrated the potential of genipin in suppressing hepatocellular carcinoma metastasis, and p38/TIMP-1/MMP-2 pathway may be involved as the key mechanism of its anti-metastasis effect.

Biocompatibility of genipin and glutaraldehyde cross-linked chitosan materials in the anterior chamber of the eye

Chitosan is a naturally occurring cationic polysaccharide and has attracted much attention in the past decade as an important ophthalmic biomaterial. We recently demonstrated that the genipin (GP) cross-linked chitosan is compatible with human retinal pigment epithelial cells. The present work aims to further investigate the in vivo biocompatibility of GP-treated chitosan (GP-chi group) by adopting the anterior chamber of a rabbit eye model. The glutaraldehyde (GTA) cross-linked samples (GTA-chi group) were used for comparison. The 7-mm-diameter membrane implants made from either non-cross-linked chitosan or chemically modified materials with a cross-linking degree of around 80% were inserted in the ocular anterior chamber for 24 weeks and characterized by slit-lamp and specular microscopic examinations, intraocular pressure measurements, and corneal thickness measurements. The interleukin-6 expressions at mRNA level were also detected by quantitative real-time reverse transcription polymerase chain reaction. Results of clinical observations showed that the overall ocular scores in the GTA-chi groups were relatively high. In contrast, the rabbits bearing GP-chi implants in the anterior chamber of the eye exhibited no signs of ocular inflammation. As compared to the non-cross-linked counterparts, the GP-chi samples improved the preservation of corneal endothelial cell density and possessed better anti-inflammatory activities, indicating the benefit action of the GP cross-linker. In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of cross-linking agents.

Engineering endostatin-expressing cartilaginous constructs using injectable biopolymer hydrogels

The release of an anti-angiogenic agent, such as type XVIII/endostatin, from an implantable scaffold may be of benefit in the repair of articular cartilage. The objectives of this study are to develop an injectable mesenchymal stem cell (MSC)-incorporating collagen-based hydrogel capable of undergoing covalent cross-linking in vivo and overexpressing endostatin using nonviral transfection, and to investigate methods for the retention of the endostatin protein within the scaffolds. The effects of different cross-linking agents (genipin, transglutaminase-2, and microbial transglutaminase) and different binding molecules for endostatin retention (heparin, heparan sulfate, and chondroitin sulfate) are evaluated. Cartilaginous constructs that overexpress endostatin for 3 weeks are successfully engineered. Most of the endostatin is released into the surrounding media and is not retained within the constructs. The presence of two common basement membrane molecules, laminin and type IV collagen, which have been reported in developing and mature articular cartilage and are generally associated with type XVIII collagen in vivo, is also observed in the engineered cartilaginous constructs. Endostatin-producing cartilaginous constructs can be formulated by growing nonvirally transfected mesenchymal stem cells in collagen gels covalently cross-linked using genipin, transglutaminase-2, and microbial transglutaminase. These constructs warrant further investigation for cartilage repair procedures. The novel finding of laminin and type IV collagen in the engineered cartilage constructs may be of importance for future work toward understanding the role of basement membrane molecules in chondrogenesis and in the physiology and pathology of articular cartilage.

Transforming growth factor beta signal transduction: a potential target for maintenance/restoration of transparency of the cornea

Maintenance of the transparency and regular shape of the cornea are essential to the normal vision, whereas opacification of the tissue impairs vision. Fibrogenic reaction leading to scarring in an injured cornea is characterized by appearance of myofibroblasts, the key player of the fibrogenic reaction, and excess accumulation of fibrous extracellular matrix. Inflammatory/fibrogenic growth factors/cytokines produced by inflammatory cells play a pivotal role in fibrogenic response. Signaling systems involved in myofibroblast formation and fibrogenesis are activated by various growth factors, i.e., transforming growth factor beta or others. Modulation of transforming growth factor beta signal transduction molecules, e.g., Smad and mitogen-activated protein kinases, by gene transfer and other technology provides a new concept of prevention/treatment of unfavorable fibrogenesis in the cornea.

Genipin enhances the mechanical properties of tissue-engineered cartilage and protects against inflammatory degradation when used as a medium supplement

Genipin is a naturally-derived biocompatible cross-linking agent commonly used to generate three dimensional tissue-engineered scaffolds or to fix biologically derived scaffolds prior to implantation. Here we propose a novel use for genipin as a long-term culture medium supplement to promote cross-linking of de novo cell products that are produced in engineered cartilage. We hypothesize that the application of genipin will stabilize the extracellular matrix components and increase the mechanical properties of developing engineered cartilage. Chondrocytes encapsulated in agarose hydrogel (a neutrally charged polysaccharide scaffold that is unaffected by genipin cross-linking) were cultured in a chemically-defined growth medium that was supplemented with varying concentrations of genipin (22 microM, 220 microM, 2200 microM) for various durations (continuous or intermittent). Tissues developed significantly higher mechanical properties (+28% dynamic modulus and +20% Young's modulus) by day 42 with genipin treatment compared to untreated controls. These increases were not immediate, but presented over culture time after genipin treatment. The genipin treated groups were also more resistant to cytokine-induced degradation with interleukin-1alpha; maintaining an E(Y) (+218%), G* (+390%) and glycosaminoglycan (GAG) content (+477%) over genipin-untreated constructs subjected to interleukin. We hypothesize two mechanisms through which the physical enhancement of tissue properties may be fostered: (1) by cross-link mediated reorganization and enhanced retention of cell-elaborated extracellular matrix components, and (2) through reduction of the loss of extracellular matrix components by increasing their resilience to catabolic degradation. These studies demonstrate a potential use of genipin as a medium supplement to develop enhanced engineered cartilage.

Comparative performance of electrospun collagen nanofibers cross-linked by means of different methods

Collagen, as the major structural protein of the extracellular matrix in animals, is a versatile biomaterial of great interest in various engineering applications. Electrospun nanofibers of collagen are regarded as very promising materials for tissue engineering applications because they can reproduce the morphology of the natural bone but have as a drawback a poor structural consistency in wet conditions. In this paper, a comparative study between the performance of different cross-linking methods such as a milder enzymatic treatment procedure using transglutaminase, the use of N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide, and genipin, and the use of a physical method based on exposure to ultraviolet light was carried out. The chemical and enzymatic treatments provided, in this order, excellent consistency, morphology, cross-linking degree, and osteoblast viability for the collagen nanofibers. Interestingly, the enzymatically cross-linked collagen mats, which are considered to be a more biological treatment, promoted adequate cell adhesion, making the biomaterial biocompatible and with an adequate degree of porosity for cell seeding and in-growth.

Inhibition of hepatic stellate cell activation following Yinchenhao decoction administration to dimethylnitrosamine-treated rats

AIM

In an effort to investigate the mechanism by which Yinchenhao decoction (YCHD) acts on liver injury, we investigated the potential antifibrogenic effects of YCHD in an experimental liver fibrosis rat model, with special focus on the mechanisms inhibiting the activation and promoting apoptosis of hepatic stellate cells (HSC).

METHODS

The rats were initially randomized into two groups: the control (n = 10) and dimethylnitrosamine-treated (DMN; n = 30) groups. DMN (10 mg/kg body weight) was administered intraperitoneally to the DMN-treated rats for three consecutive days each week. At the end of the second week, three rats from the control and six rats from the DMN-treated groups were killed for the fibrosis development assessment. The remaining DMN rats were further randomized into two groups: the DMN-water group (n = 12) and the DMN-YCHD group (n = 12). Both groups continued to receive weekly DMN treatment for another 2 weeks in addition to daily administration of either water or YCHD, which were given intragastrically at a dose of 0.418 g/100 g body weight.

RESULTS

Hepatic hydroxyproline content decreased and had improved histopathology in the DMN-YCHD rats. Compared to the DMN group, alpha-smooth muscle actin (SMA) and CD68 expression in the DMN-YCHD group was reduced significantly; however, alpha-SMA-positive HSC apoptosis was not observed by confocal microscopy; Fibrogenic proteins (tissue inhibitor matrix proteinases-1 and 2 and matrix metalloproteinase [MMP]-2/14) and cytokines (tumor necrosis factor-alpha and transforming growth factor-beta(1)) were decreased; MMP-9 was significantly upregulated.

CONCLUSION

Yinchenhao administration attenuates liver fibrosis at least in part by inhibiting HSC activation directly, rather than promoting cell apoptosis of activated HSC, and the suppressive activation of Kupffer cells.

The anaphase-promoting complex coordinates initiation of lens differentiation

Lens development requires the precise coordination of cell division and differentiation. The mechanisms by which the differentiation program is initiated after cell cycle arrest remains not well understood. Cyclin-dependent kinase inhibitors (CKIs), such as p15 and p21, have been suggested to be critical components that inhibit G1 progression and therefore, their activation is necessary for quiescence and important for the onset of differentiation. Regulation of p15 and p21 is principally governed by transforming growth factor (TGF)-beta-signaling pathway. We have identified that Cdh1/APC, a critical ubiquitin protein ligase, plays an important role in regulating lens differentiation by facilitating TGF-beta-induced degradation of SnoN, a transcriptional corepressor that needs to be removed for transcriptional activation of p15 and p21. The depletion of Cdh1 by RNA interference attenuates the TGF-beta-mediated induction of p15 and p21 and significantly blocks lens differentiation. Expression of nondegradable SnoN also noticeably attenuates lens induction. Furthermore, we have shown that Cdh1 and SnoN form a complex at the onset of lens differentiation. In vivo histological analysis confirms our biochemical and genetic results. Thus, Cdh1/APC is crucial to the coordination of cell cycle progression and the initiation of lens differentiation through mediating TGF-beta-signaling-induced destruction of SnoN.